private static void RegisterCommandHandlers(IConcertService concertService, CommandHandlerCollection commandHandlers)
        {
            var factory = new SimpleEventHandlerFactory();

            commandHandlers.AddHandler(typeof (PurchaseTicketCommand), factory.CreateEventHandler(concertService,
                (IConcertService service, IPurchaseTicketCommand cmd, long seq, bool endOfBatch) =>
                {
                    concertService.PurchaseTicket(/*IPurchaseTicketCommand data*/);
                }));

            commandHandlers.AddHandler(typeof(CancelTicketCommand), factory.CreateEventHandler(concertService,
                (IConcertService service, ICancelTicketCommand cmd, long seq, bool endOfBatch) =>
                {
                    concertService.CancelTicket(/*ICancelTicketCommand data*/);
                }));

            commandHandlers.AddHandler(typeof(CreateConcertCommand), factory.CreateEventHandler(concertService,
                (IConcertService service, ICreateConcertCommand cmd, long seq, bool endOfBatch) =>
                {
                    concertService.CreateConcert(/*ICreateConcertCommand data*/);
                }));
        }